With the increasing of people's life level, a demand for high-quality speaker systems has increased dramatically over the last twenty years. At present, a traditional speaker system generally can produce a stereophonic effect with a plurality of channels by setting a set of stereophonic speaker assembly.
For example, a typical stereophonic speaker assembly includes a pair of primary loudspeakers and a pair of secondary separate loudspeakers to form four sound emission fields. However, such a speaker assembly is tack of a sense of three-dimensional depth. Stereophonic effect can only be enjoyed at a middle location between the two loudspeakers. If the listener is adjacent to one loudspeaker but is far from the other loudspeaker, the stereophonic effect is significantly decreased. Further, in this structure, the speaker assembly occupies a large space in a room and it is inconvenient to carry and move away.
Some stereophonic speaker assemblies can achieve surround sound effect by a surround sound system. The surround sound system simulates a desired three-dimensional environment by directing sound to the listener from various orientations, including front, side, back, floor and ceiling propagation. Modem surround sound systems capitalize on diverse speakers to generate both stereophonic and multi-channel output, as well as synchronized shifting of isolated sounds to individual speakers disposed around the listener. For example, a speaker assembly is equipped with a speaker array constituting a 5.1ch surround sound system, e.g., a front left channel, a front right channel, a center channel, a rear left channel, a rear right channel, and a subwoofer LFE(Low Frequency Effects)ch.
However, such speaker assembly with a speaker array requires a complex structure and technology, and at the same time this brings about many undue problems. For example, the wiring for coupling the loudspeakers to a sound source makes the room untidy. In effect, this complex speaker assembly has disadvantageous influence on interior decoration. Furthermore, requirement for multi-direction separate loudspeakers results in an expensive cost of such speaker assembly.
At present, some speaker assemblies use a digital process technology to obtain desired surround sound effect. This digital speaker assembly typically includes a speaker array apparatus. The speaker array apparatus includes a plurality of speaker units from which audio is outputted and reflected with directivity against a predetermined wall surface or a reflection plate so as to form a virtual speaker. Each of the plurality of speaker units is independently driven so that an audio beam generated according to the input audio signal by a digital signal processor is emitted to a predetermined focal point position in a space. Although this digital speaker assembly enables realization of a wide listening range and a sound image positioning, it requires a very complex digital circuit system and various electronic elements. This increases complexity of design, as well as cost of the product. The high expensive product suppresses wide application of the digital speaker assemblies.
There is, therefore, a need for a multi-directional sound emission system, which has a compact structure and a reduced cost, and is portable and easy to assemble.